Disclosed herein are embodiments of hydration bladders that include flexible wall portions along with relatively more rigid structural portions that are shaped to help define the shape of the bladder and can also help a user grip and manipulate the bladder. The structural portions can also support or incorporate other bladder features, such as inlet ports, caps, outlet ports, valves, tubes, attachment points, graphic designs, and/or other features. Some embodiments include an outlet tube that is retractable and extendable through an upper port at the top of the bladder.